The instructions come shortly after we’ve confirmed the booking. “Our venue is located behind a black steel door inside a small gelato shop… Please open the door carefully and make your way upstairs.”

It couldn’t feel more Japanese. But then, it’s all very Melbourne, too – the nondescript entry, accessed through a gelateria that’s pumping despite the frigid midwinter weather. Once upstairs, however, Melbourne melts away.

Leonie Upstairs’ arrival felt as covert as its doorway, popping up without fanfare in April above Hareruya Pantry and Bar Holiday in a formerly bland corner of Carlton. Co-owned by chef Kantaro Okada, Leonie is named for the culture-straddling American intellectual Leonie Gilmour, mother of sculptor Isamu Noguchi.

The space is inspired by her son’s minimalist influence, all immaculate blond-wood joinery, white brick walls and Akari paper lanterns.

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Behind the mezzanine bar seats, ikebana flower arrangements share the wall with abstract photographic prints.

A menu encompasses classic Japanese drinking snacks such as tempura, house-made pickles and plump, fried oysters – juicy inside, panko-crispy out.

The popular izakaya dish takowasa, of raw octopus with a nasal-cleansing punch of wasabi, is marinated with salted kombu. Scallop carpaccio dressed with pansies, dill fronds and ruby-red grapefruit is gorgeous to look at, but the citrus almost overpowers the delicate mollusc. From the “broth” section comes chawanmushi – a joyous little bowl of textural surprises, from silken egg custard to pops of salmon roe, fried eel and crisp snow peas. The oden is a cockle-warming concoction with a chicken meatball, tofu skin and daikon afloat in a dashi broth.

The signature cone-shaped temaki sushi is hand rolled to order with high-grade Japanese rice scooped from a wooden hangiri bowl, with morsels such as gelatinous pearls of flounder fin (engawa) draped atop the sticky grains.

The fresh-rolled nori sheet contributes crunch and flavour you won’t find in your average sushi roll. It’s tempting to return just for the DIY temaki set, which comes with an array of fresh veg and seafood ready to roll.

Sake takes an equal footing to food, with a list topping out at 50 different bottles (without a single wine). Sensing our decision paralysis, the waiter steers us towards the recently introduced sake flights and walks us through a tasting.

The “Intro to sake” is designed for rookies, showcasing basic styles of sake as determined by the milling of the rice.

For something more adventurous, the single-brewery tasting flights offer three expressions from one maker – this month a rule-bending trilogy from Kinoshita Brewery by Philip Harper, the first foreigner to earn the venerated title of Toji (master sake maker).

For dessert, the blue cheesecake combines three cheeses with a hint of yuzu; more dense and satisfying than the typical souffle-style Japanese version (even if it could stand a minute more out of the fridge before serving).

Venturing back downstairs as the clock nears 11pm and the temperature dips into single digits, the gelato queue is just starting to thin – the last punters clinging to a taste of Japan in this corner of Melbourne.

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